To create your MyEtherWallet start here.
Be sure to pay attention to the URL at the top of the page. It should match the one in the picture. (When setting up your MEW wallet you will not be able to hit the back button so pay close attention and save everything as you go. You may want to make screen shots of your information so as to not lose track.)
Step 1: Enter your password and click "Create New Wallet" remember that passwords containing a combination of letters, numbers, and symbols are most secure.
Step 2: Download and save your Keystore File. You may want to copy it to more than one place. It is important to note that there is no way to recover this file once you click continue.
Step 3: Save your private key by copying and pasting it to a document or writing it down somewhere safe. Print your paper wallet and store it safely as well. Then continue to save your address.
Step 4: Here you can choose how you want to access your account. If you have a MetaMask wallet you can quickly add your new MEW wallet by selecting MetaMask from the list. Otherwise click Private Key and continue.
Step 5: Make sure to copy your address and add it to your Refereum.com account. Remember DO NOT SHARE YOUR PRIVATE KEY with anyone.
You are all set!!
You are ready to go!!